1. Field of the Invention
The present invention relates to a system and method for obtaining performance data from a communication access method (CAM) employed to operate a network. More particularly, the present invention relates to a system and method by which a CAM is adapted to deliver formatted network performance data upon request to a predetermined module from which the data is collected by a network performance monitor for further processing thereof.
2. Description of the Related Art
Communication access methods (CAMs), such as VTAM, which is a trademark of the IBM Corporation, are routinely employed to harness the power of mainframe computers for multiple users. CAMs permit the computer to be employed in operating a variety of resources, such as terminals, printers and other peripheral devices, and allow customers/users of the overall computer system to engage the computer and use the available resources. That is, CAMs allow customers/users to share the processing power of a mainframe computer and give them access to the resources associated with the computer.
Given the necessary complexity Of CAMs and the differing requirements of each set of customers/users, a need for a means to monitor the performance of CAMs developed. Network performance monitors (NPMs) were developed to fulfill this need. An NPM obtains transit time and volume statistics from a CAM and processes the statistics to provide performance data to a system operator. Depending on the requirements of the customers/users, the system operator may use the performance data to modify the CAM so as to better serve the customers/users. Modifications can include speeding up certain functions, changing priorities, providing more equitable access to certain resources, etc.
However, CAMs were not designed with NPMs in mind, and therefore interfacing between an NPM and a CAM is presently quite awkward. One function of NPMs is to obtain transit times for transactions which are using the network manager system. To carry out this function, NPMs collect session statistics for transactions. These statistics consist of transit times and volume measurements. To obtain the transit time, the NPM sums the host time and network time for a given transaction as calculated at the internal processing portion of the CAM. This is accomplished by monitoring for path information units (PIUs) associated with the given transaction. Host time is calculated by subtracting the time an outbound PIU passes the internal processing from the time the preceding inbound PIU passes the internal processing, while network time is typically calculated by subtracting the time the outbound PIU passes the internal processing from the time the subsequent inbound PIU passes thereby. Volume measurements are typically the number of bytes contained in each inbound and outbound PIU at the internal processing. The volume measurement includes both system data bytes and user data bytes. System data is defined as that part of a PIU involved in session control on behalf of the user. User data is defined as that part of a PIU involved in processing the user's transaction. The problem in obtaining this data arises in that no means exists in any existing CAM that was designed to cooperate with a network performance monitor, and the NPM must take over portions of the internals of the CAM to obtain the data. One such present procedure is described below.
Typically, a CAM such as VTAM includes a buffer trace function. The customers lusers of the system employ the buffer trace function to identify problems with hardware or software in their network. Presently, session statistics can be gathered by the network performance monitor utilizing the buffer trace function or other internal functions of the CAM. The network performance monitor intercepts internal calls of the CAM and reads control blocks from the CAM. More specifically, the NPM hijacks the buffer trace and activates it for a desired resource. The network performance monitor intercepts calls to the buffer trace of the CAM and gathers information regarding the appropriate PIUs from control blocks of the CAM by copying the desired information into control blocks of the network performance monitor. The data is then processed in the network performance monitor through known methods, such as those described above, in order to obtain the appropriately processed data. This processed data is then used to adjust the operating parameters of the CAM to improve or adjust performance of the CAM as desired.
As mentioned above, this process has a number of drawbacks. First, this use of the buffer trace function of the CAM interferes with the ability of customers/users of the computer to use the buffer trace function to monitor for hardware and software errors in the network. Further, the customers/users have no means to manage this concurrent use of the buffer trace. Additionally, the network performance monitor is dependent upon internal details of the CAM, such as resource addresses as defined by the CAM. Any changes to the CAM, such as the changing of an address of a resource or the installation of a new release of the CAM, requires that the network performance monitor be appropriately modified to compensate for these changes. Serviceability is also a problem, since a problem in one product can manifest itself as a problem in the other product, due to the common internal processing routines.